• The korean journal of orthodontics
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• v.39 no.3
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• pp.185-198
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• 2009

Tooth anklylosis is defined as the adhesion state of alveolar bone to dentin or cementum. Trauma, disturbed metabolic disease, and congenital disease have been given as etiologic factors. Complications of tooth ankylosis are tipping of the neighboring teeth, space loss, and supraeruption of the opposing teeth. Particularly if dental ankylosis occurs in maxillary incisors of a growing child, the ankylosed tooth can not move vertically with subsequent disturbance in vertical growth of the alveolar process. With an appropriate treatment approach, an esthetic condition must be achieved especially in the maxillary anterior region. In this report, two cases are presented which were treated by the surgical repositioning method. One is treated by alveolar bone distraction osteogenesis which used a tooth-borne type distraction device and the other by single tooth osteotomy.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.188-197
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• 2010

The purpose of this study was to compare radiopacity and radiographic discriminability of various FRC-Posts. Six FRC-Posts were investigated ; 1) FRC Postec Plus (Ivoclar Vivadent AG, Schaan, Liechtenstein), 2) Snowlight (Carbotech, Lewis center, OH, USA), 3) Dentin Post (Komet Brasseler, Lamgo, Germany), 4) Rely-X Fiber Post (3M ESPE, St.paul, MN, USA), 5) D.T.-Light Post (BISCO, Schaumburg, IL,USA), 6) Luxapost (DMG, Hamburg, Germany) The radiographs of each post with a reference 1 mm / 2 mm aluminum step-wedge was taken using digital sensor. The optical density were calculated by gray value of $10{\times}10$ pixel and compared in mm Al equivalent at five points. Six maxillary incisors of similar radiopacity were used. Radiographs of posts in Mx. incisors of lingual side of dry mandible were taken. We showed radiographs and asked the questionnaire to 3 radiologists, 3 endodontists, 3 general practitioners. The questionnaire was comprised of choices of the highest, lowest radiopaque individual post and the choices of best discriminable post at apical, coronal area. The following results were obtained. 1. Each post system showed various radiopacity. 2. There was change of discriminability between each post and simulated specimens regardless of examiner. Although each post showed various radiopacity, the difference of radiopacity did not affect on discriminability.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.96-101
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• 2009

Regional odontodysplasia(ROD) is relatively rare localized developmental anomaly of tooth formation in which hard tissue is affected. The maxilla is typically affected than the mandible, and especially the maxillary left quadrant is the most commonly involved. Females are affected twice as often as males, and there is no association with race. Its etiology remains undetermined, but local circulatory disorders, somatic mutations, virus infections, local trauma, hyperpyrexia, irradiation, metabolic disturbances, and hereditary transmission are considered as possible etiologic factors. The affected teeth are likely to be small, hypoplastic, brown, and grooved. Eruption failure or delay is frequently seen as well as abscess or fistulae formation in absence of caries. Radiographically, there is a lack of contrast between the enamel and dentin, both of which are less radiopaque than unaffected counterparts. Moreover, enamel and dentin layers are thin, giving the teeth a “ghost-like appearance”. The pulp chambers and canals are large, the roots seem like to be short and indistinct. A 2-year-3-month old boy came to the department of pediatric dentistry, Yonsei University, with the chief complaint of delayed eruption and abnormal tooth shape on the lower left quadrant. He was diagnosed as regional odontodysplasia based on the clinical and radiographic findings.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.455-467
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• 1996

This study was designed to evaluate the expression of type I collagen in periodontal tissue during the experimental movement of rat incisors. Twenty-one Sprague-Dawley rats were divided into a control group(3 rats), and experimental groups(18 rats) where a force(75g) from helical springs across the maxillary incisors was applied. Experimental groups were sacrificed at 12 hours, 1, 4, 7, 14 and 28 days after force application, respectively. And tissue slides of control and experimental groups were studied histologically and immunohistochemically by LSAB(Labelled streptavidine Biotin) immunohistochemical staining for type I collagen. The results were as follows: 1. Until 28-day after force application, periodontal fibers were strectched on the tension side, and compressed in pressure side, and the arrangement of periodontal fibers was not recovered by that time. 2. The degree of type I collagen expression in control group was rare in the oral epithelium, predentin, pulp and periodontal ligament, but was mildly positive in osteoblasts, acellular cementum, cementoblasts, intermaxillary suture. 3. At acellular cementum of experimental group, the expression of type I collagen was moderate in 1-day and severe in 7-day, which was maintained until 28-day. 4. Type I collagen was observed in the newly formed fibrous connective tissue and osteoblasts at intermaxillary suture, moderately in 1-day, and severely in 14-day. 5. The tension side of periodontal ligament showed a more positive expression of type I collagen than the pressure side in 4-day. The degree was highest in 7-day and was not differentiated between sides in 14-day. 6. In the side wall of bone matrix on which osteoblasts were attached, type I collagen was expressed severely, especially in 7-day. From the above findings, we could suggest that bone remodeling in tooth movement be intimately related to the cell differentiation and the resulting formation of type I collagen.